Writing tool

ABSTRACT

A writing instrument having a mechanism for advancing and retracting the writing member, e.g. a cartridge disposed in the housing of the writing instrument, and a clip provided laterally on the housing to secure the writing instrument to a pocket. The mechanism is so constructed that the retraction of the writing member can be effected optionally by actuating a pushbutton provided on the rear end of the housing or by lifting the clip in relation to the longitudinal axis of the housing.

United States Patent Bross WRITING TOOL [72] Inventor: Helmut Bross,Biberttalstrasse 24, Altenberg near Nuremberg, Germany [22] Filed: May21, 1970 [211 App]. No.: 41,666

Related 0.8. Application Data [63] Continuation of Ser. No. 758,829,Sept/l0, 1968,

abandoned.

[30] Foreign Application Priority Data Sept. 12, 1967 Germany ..P 15 61807.2

[52] U.S.Cl ..40l/l04, 401/107, 401/198 [51] Int. Cl ..B43k 5/16 [58]Field ofSearch ..40l/198,199, 104-116 [56] References Cited UNITEDSTATES PATENTS 2,809,609 10/1957 Clary et a]. ....401/105 [451 Jan. 25,1972 2,930,356 3/1960 Liguori ..401/113 2,957,452 10/1960 Brannon......401/108 3,288,114 11/1966 Ritter ..401/l04 3,334,615 8/1967 Bross401/110 3,427,114 2/1969 Dzink "401/199 FOREIGN PATENTS OR APPLICATIONS1,379,338 10/1964 France ..401/104 Primary Examiner--Lawrence CharlesAttorney-Spencer & Kaye 57 ABSTRACT A writing instrument having amechanism for advancing and retracting the writing member, e.g. acartridge disposed in the housing of the writing instrument, and a clipprovided laterally on the housing to secure the writing instrument to apocket. The mechanism is so constructed that the retraction of thewriting member can be effected optionally by actuating a pushbuttonprovided on the rear end of the housing or by lifting the clip inrelation to the longitudinal axis of the housing.

2 Claims, 16 Dr w n F .9.???

PATENTED 11251972 $537,31 sum 1 or z 52' 1.9 FIG.30

FIG. 4

F|G.Ib so 4 F196 52 INVENTOR.

Helmun Brass PATENWU m2 5 m2 sum 2 OF 2 21. 7 2s 25 as as s INVENTOR. He lmu+ B r0 BY fl/forneys 5 This application is a continuation ofapplication Ser. No. 758,829, filed Sept. th, I968 by Helmut Bross, andnow abandoned.

BACKGROUND OF THE INVENTION The present invention relates to writinginstruments such as ballpoint or felt pens.

Writing instruments are known which comprise an operating member axiallydisplaceably mounted on the rear end of the housing of the instrumentand adapted to be operated by finger pressure, and a writing member, forexample, a cartridge disposed in the housing, displaceable under oragainst the action of a spring. The spring tends to move the writingmember from a forwardly shifted position in which the writing point ofthe writing member projects out of the forward end of the housing, and aretracted position in which the writing point is concealed by thehousing, the said member being securable in these positions. In manycases,- a shifting mechanism is provided which comprises a lockingelement which is adapted to be pushed, under the pressure of theactuating member or of the spring, against guide surfaces formed on ashifting member, on which guide surfaces the locking element is movedtransversely in relation to the longitudinal axis of the housing and isthus brought into the region of stops provided on the shifting memberand is caused to bear against the stops, the bearing of the lockingmember against one of the stops fixing the writing medium holder in oneof the two positrons.

More especially in writing instruments in which the writing point is fedwith ink, e.g., in the felt pens which have recently become increasinglywidely employed, and in which the writing member is formed of a bundleof fibers, it is found desirable to provide means to ensure that thewriting instrument is not put into the pocket with the writing pointprojecting from the housing, which would result in very undesirablesoiling of the clothing. A known safety measure of this type, in caseswhere there is provided on the outside of the housing of the writinginstrument a securing clip which can be bent over so as to increase thedistance between it and the housing wall and so as to set up asubstantially resilient return force, consists in so designing thearrangement that, as a result of the positive bending-over of the clipwhen it is pushed on to the wall of a pocket, the cartridge isautomatically. released from its forwardly pushed position and therebybrought into its retracted position under the action of the compressionspring. In the known writing instruments of this kind, the disadvantageexists that the cartridge can only be brought out of the forwardlypushed position into the retracted position by bending-over of the clip.Therefore, the clip must also be actuated when the user of the writinginstrument wishes to bring the cartridge into its retracted positionbefore pushing the clip on to the wall of a pocket. The movement of thecartridge from the retracted position into the forwardly pushed positionin the known writing instruments takes place by depression of anoperating member provided on the rear end of the housing. It

is troublesome for the user to manipulate the shifting mechanismdifferently depending upon the position in which the cartridge issituated, and this substantially impairs the usefulness of such awriting instrument.

SUMMARY OF THE INVENTION According to the present invention there isprovided a writing instrument comprising a housing, an operating memberaxially displaceably mounted in the rear of the housing, fordisplacement by finger pressure, a spring mounted within said housing, awriting member within said housing and having a writing point adjacentthe forward end of said housing and axially movable rearwardly under theaction of said spring to a retracted position, in which the writingpoint is within the housing, and axially movable by said operatingmember to a forward position in which the point projects from theforward end of the housing, locking means releasably locking the writingmember in the forward position, stops to arrest the writing member inthe forward and retracted positions, a securing clip externally of thehousing, and means associated with the operating member and with thesecuring clip to release the locking means either by depressing theoperating member or by lifting the clip away from the housing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. la is an elevational view, mostlyin section, of one embodiment of writing instrument according to theinvention, in the form of a felt pen, with the cartridge in theretracted position;

FIG. lb is an enlarged longitudinal section through the writing end ofthe felt pen of FIG. 1;

FIG. 2 illustrates the writing instrument shown in FIG. 1, with thecartridge in the forwardly shifted position;

FIG. 3a is an enlarged longitudinal section through the writing end of afelt pen according to the invention, wherein the means for preventingsoiling of the inside wall of the housing, lying in the region of theforward aperture of the housing, is modified as compared with theembodiment illustrated in FIGS. 1 and 2;

FIG. 3b is a front view of cap'according to the present invention;

FIG. 4 is an enlarged plan view of the outside of a housing part of awriting instrument according to the invention, wherein the guidesurfaces and stops cooperating with the locking member are formed on theoutside of the housing;

FIG. 5 is a side view of the lower end of a securing clip on which thereis provided a locking element which cooperates with guide surfaces andstops provided on the outside of the housing;

FIG. 6 is an illustration corresponding to FIG. 4, but drawn to asmaller scale, of an embodiment in which the guide surfaces and stopsformed on the outside of the housing are differently arranged from thoseof FIG. 4;

FIG. 7 is a longitudinal section through the rear end of a writinginstrument according to the invention, wherein the securing clip isconnected to a pushbutton adapted to be swiveled when it is lifted inthe housing, the cartridge here being situated in the retractedposition;

FIG. 8 illustrates the embodiment illustrated in FIG. 7 with anarrangement of the parts associated with the shifting mechanism whichcorresponds to the forwardly pushed position of the cartridge;

FIGS. 9 and 10 are longitudinal sections through the rear end of twoembodiments of the invention, wherein the stops and guide surfaces forthe locking member are provided on a part situated within the housingand axially displaceable therein;

FIG. 11 is a longitudinal section through the rear end of an embodimentin which the stops and guide surfaces for the locking member are againformed on a part displaceable within the housing, the locking memberbeing provided on a securing clip;

FIG. 12 is a view of a shifting mechanism corresponding to FIG. 11,wherein the stops and guide surfaces for the locking member are ofdifi'erent construction;

FIG. 13 is a longitudinal section through the rear end of a furtherembodiment, wherein the abutments and guide surfaces for the lockingmember are again provided on a part axially displaceable in the housing,the locking member being formed in this case on a tongue formed by anincision in the housing wall; and

FIG. 14 is a plan view of FIG. 13 as seen in the direction of the arrowA.

DESCRIPTION OF THE PREFERRED EMBODIMENT Pans having correspondingfunctions are denoted by the same reference numerals in the variousfigures. The terms lower and upper" are used to denote those portionsnearer to, and further away from the writing end of the instrumentrespectively.

In the figures, the housing 1 of the writing instrument, which isconstructed either in one piece or in a number of parts, has axiallyslidable therein a writing member or cartridge 2. A pushbutton 3 mountedon the rear end of the housing is also axially displaceable in thelatter, to move the cartridge 2 forward against the action of acompression spring 4 disposed in the forward part of the housing andbearing at one end against the cartridge 2 and at its other end againsta projection on the inside of the housing. Near to its rear end thehousing is provided with a securing clip 5. In each of the embodimentsthe cartridge 2 may be releasably locked in the forward position by alocking member.

In the embodiments illustrated in FIGS. la, lb, 2., 4, 5 and 6 thelocking member is constructed as an extension 6 projecting from thatside of the clip 5 which is closer to the housing 1. The clip 5 consistsof a bent-over portion, at its upper end extending away from the housing1, a central portion substantially parallel to the housing and a portion5' at its lower end which slopes away from the housing to facilitate theintroduction of the material 7 of a pocket wall between the lockingmember 6 and the housing I.

The stops and guide surfaces for the locking member may be positionedand formed on the outside of the housing as illustrated in FIGS. 4 and6. In the embodiment according to FIG. 4, the housing is polygonal and agroup of three guide surfaces are disposed at different distances fromthe longitudinal axis of the housing and inclined in the same direction.The uppermost and central guide surfaces 8 and 9 respectively are formedon a projection 11 of the housing, while the lowermost guide surface iscreated by a step descending from a surface 14 to a surface 12 which isat a shorter distance from the longitudinal axis of the housing than thesurface 14. At that end of the central guide surface 9 which is closerto the pushbutton 3, a stop for the locking member which becomesoperative when the cartridge is in' the forwardly pushed position, isformed by a stop surface 13 extending parallel to the longitudinal axisof the housing and also formed on the projection 11.

In the embodiment according to FIGS. Ia, lb and 2, a special stop forthe locking member 6 when the cartridge is in the retracted position isnot required, because the latter is held in the retracted position bythe same stop which becomes operative on lifting of the securing clipand which will hereinafter be described. The stop surface 13 performs afurther function, in that, when the locking member 6 passes from theuppermost guide surface 8 to the central guide surface 9, it preventsthe locking member from being deflected as far as the surface 15 of thetransfer region from the lowermost guide surface 10 to the uppermostsurface 8, and skipping the position in which the pushed-forwardcartridge is arrested. As will readily be seen, such a deflection wouldresult in errors in the shifting movement. The surface 15 of thetransfer region rises up to the level of a surface 16, which descends inone step to a surface 17 which is consequently at a shorter distancefrom the housing axis than the surface 16. It will be understood thatthis step forms a boundary of the uppermost guide surface 8. The surface17 is also closer to the longitudinal axis of the housing than thesurface 14, the two levels being joined by a sloping surface 18 whichrises from the surface 17. Also provided for the locking member is astop surface 19 on a strip-form projection 20 formed on the housing, anda further stop surface 21 formed by a step situated at the lower end ofthe surface 12 and rising therefrom, these stop surfaces sloping in thesame direction as the guide surfaces 8 to 10.

When the pushbutton 3 is actuated, the path described by the lockingmember 6, shown in phantom in FIG. 4, is illustrated by a dash-dottedarrowed line. When the pushbutton 3 is depressed from the retractedposition, the locking member is first pushed against the guide edge 8and is thus first deflected transversely in'relation to the longitudinalaxis of the housing. As soon as the locking member has left theoperative range of the guide surface 8, it slides along a longitudinalguide surface 22 formed on the projection ll. As soon as the lockingmember has left the guide surface 22, it abuts the stop 19 and springsback about the axis of the holder, and enters the operative region ofthe central guide surface 9, on which it slides until it encounters thesurface 13. The pushbutton 3 and, thus, also the cartridge 2, is therebyarrested in its forwardly pushed position (see FIG. 2). The deflectionof the locking member after it has slid off the guide surface 22 in thedirection of the central guide surface 9 takes place under the action ofthe resilient return force which has been produced in the clip 5 by thepreceding lateral deflection in the course of the pressure of thelocking member 6 against the guide surface 8. As soon as the lockingmember 6 has entered the operative region of the guide surface 9, it ispressed against the guide surface 9 by the pressure exerted on thecartridge by the spring 4 and transmitted through the pushbutton 3 andthe securing clip 5, so that the locking member can slide along thissurface until it encounters the surface 13.

When the pushbutton 3 is pushed downwards from its forwardly pushedposition (FIG. 2) the locking member 6 falls on to the surface 12 and,on release of the pushbutton, abuts the guide surface 10 owing to thepressure of the spring 4, and slides along the said guide surface 10under the further pressure of the spring 4. As soon as the lockingmember 6 has left the guide surface 10, it slides along the longitudinalguide surface 23 on the projection 11 and finally returns into itsinitial position, which corresponds to the retracted position of thepushbutton and thus also of the cartridge. The bearing of the workingsurfaces of the locking member 6, which is of rhomboidal form as seen inplan view, on the guide surfaces 8 to 10 is also ensured by a resilientreturn force which acts on the clip 5 to push the clip and thus also thelocking member 6 in the direction of the housing wall. The clip 5consequently forms a rocking arm which can be radially and transverselydeflected in relation to the longitudinal axis of the housing against aresilient return force, the deflectability being promoted by virtue ofthe fact that the web which connects the securing clip to the pushbuttonhas a region 5" of reduced thickness. With regard to the stop surfaces19, 21, it is also to be noted that they limit the forward displacementof the locking member and thus also of the pushbutton from the retractedrest position or from the advanced rest position. In the embodimentillustrated in FIGS. 1 and 2, there is formed on the pushbutton 3 afurther rocking arm 24 which lies within the housing I and can be bentover towards the longitudinal axis of the housing against the action ofa resilient return force. Situatedon the free end of the rocking arm isa pawl 25 which,when the cartridge is in t the forwardly pushedposition, is pressed against the inside wall of the housing I owing tothe aforesaid resilient return force (FIG. 2). When the clip 5 islifted, for example, due to the fact that the writing instrument ispushed on to the wall 7 Y of a pocket (see FIG. 1 the arresting member 6becomes disengaged from the stop by which it is fast in its forwardlypushed position. The cartridge and the pushbutton 3 are then shiftedbackwards until the pawl 25 engages, in the course of this displacement,in a recess 26 formed in the longitudinal path of movement of the pawlon the housing. The cartridge,

and thus also the pushbutton, is arrested in its retracted position.

In the embodiment illustrated in FIGS. la, lb and 2, the pushbutton 3 iscountersunk in the housing 1, so that it can be actuated by axialpressure exerted on a roughened surface 5 on the upper end of the clip5. The web 5", by which the clip is connected to the pushbutton, isguided along in a slot 27, whereby the pushbutton is secured againstrotation.

It will be seen from the foregoing description that the transfer of thecartridge from the position according to FIG. 2 into the positionaccording to FIG. I may' be effected 0ptionally by exerting an axialpressure on the pushbutton or by lifting the clip 5 from the housing 1.

The formation of the guide and stop surfaces for the locking member onthe outside that the housing, which is preferably injection-molded fromplastics, can readily be formed. The pushbutton 3, the clip 5 and therocking arm 24 may also be formed as an integrally formed plastics part.Instead of the guide and bearing surfaces being formed as illustrated inFIG. 4, these surfaces may be formed as illustrated in FIG. 6 in whichthe housing is circular in section. In contradistinction to thearrangement according to FIG. 4, the guide surfaces 28, 9 and situatedone above the other in the arrangement according to FIG. 6 are not allinclined in the same direction. The slope of the uppermost guide surface28 is in this case opposite to the slope of the other two guide surfaces9, 10, which are inclined in the same direction. In other respects,there is no basic difference between the arrangements illustrated inFIGS. 4 and 6. The manner of operation of the arrangement illustrated inFIG. 6 will be readily apparent from the dash-dotted path of movement ofthe locking member. In this case a stop surface 29 is provided, which,on the transfer of the locking member from the central guide surface tothe lowermost guide surface, prevents the locking member from beingdeflected towards the region of transfer from the uppermost guidesurface to the central guide surface.

In the embodiment of FIGS. 7 and 8, the clip is connected to apushbutton 3 which is adapted to swivel in the housing 1 when the clipis lifted from the latter. The swiveling takes place about an axis whichis at a right angle to the longitudinal axis of the housing. Two rockingarms 24, 30 are formed on the lower end of the pushbutton 3. The rockingarm 24 is comparable in its function to the rocking arm 24 in theembodiment according to FIGS. 1 and 2; it consequently also comprises alocking pawl 25 which is adapted to engage in an aperture 26 in thehousing wall 1. As with the clip 5 of FIGS. 1 and 2, there is formed onthe free end of the other rocking arm 30 a locking member 6' whichcooperates with guide surfaces and stops which in this case are formedon the inside of the housing. The stops situated one above the other inrelation to the longitudinal axis of the housing are denoted by 31 and32. The stops 31 here serves to arrest the locking member when thecartridge is in the forwardly pushed position (FIG. 8), while thelocking member 6' is adapted to engage against the stop 32 when thecartridge is in the retracted position. In the position illustrated inFIG. 7, the cartridge is situated in the retracted position, but thestop 32 is here not operative, since the return of the cartridge fromthe forwardly pushed position has been effected, not by depression ofthe pushbutton 3', but by lifting of the clip 5. In this instance, thestop formed by the wall of the aperture 26 provided in the housing forthe locking pawl 25 takes effect, which stop can become operativeindependently of the stop 32 of the actual shifting mechanism. When thesecuring clip 5 is lifted from the housing 1, the locking member 6' isdisengaged from the guide surfaces and stops of the shifting mechanismdue to the fact that the pushbutton 3' is swiveled within the housing Ias a result of the lifting action, which is clearly apparent oncomparison of FIG. 8 with FIG. 7. Also provided on the pushbutton 3 isan extension 33 which projects from the lower end thereof and which actsas a push member for the cartridge. It is advantageous for a reliableoperation of the embodiment illustrated in FIG. 7 and 8 for the clip 5to be substantially rigidly constructed, so that radial deflection ofthe clip in relation to the longitudinal axis of the housing immediatelyresults in swiveling of the pushbutton.

The embodiments illustrated in FIGS. 9 and 10 have in common the featurethat the stops and guide surfaces for the locking member are provided onknown forms of component 34 axially movable within the housing, underthe action of the spring 4, from a forward position in which thecartridge is situated in its forwardly pushed position, into a rearposition in which the cartridge is situated in its retracted position.FIGS. 9 and I0 illustrate the forwardly pushed position. The clip 5,which is separate from the pushbutton 3", is so held in the reof thehousing affords the advantage I gion of its upper end on the housing 1as to be capable of springing in a radial direction, comprises a lockingpawl 25 which extends through an aperture 26 in the housing wall and bymeans of which the component part 34 can be arrested in its forwardposition.

In the embodiment illustrated in FIG. 9, the outside surface of thecomponent 34 is for this purpose formed with an annular slot 35 in whichthe locking pawl 25 can engage. Only when the clip is lifted from theslot 35 by introduction of material 7 between the clip and the housingwall can the component 34 shift into the retracted position, theshifting movement stopping as soon as the upper end of the component 34encounters the flange 36 on the pushbutton 3", which in turn bearsagainst an inwardly projecting shoulder 37 of the housing 1. The actionof this stop is again independent of the stop formed on the inside ofthe component 34 for the retracted position of the locking member 6". Onthe inside surface of the component 34 are fonned the guide surfaces forthe locking member and the stop for its forward position. The stops aresituated at the ends of slots which extend to alternate distancestowards the rear, the guide surfaces being formed on the forward end ofthe webs remaining between the slots. Rotational movement of the lockingmember is brought about by virtue of the fact that, on depression of thepushbutton, sloped flanks on outwardly radially extending projections38' of a driving member 38 are pushed against sloped flanks of theradially extending projections 6a of the locking member 6". Theprojections 38', 611 thus slide one upon the other, whereby theprojections 6a are brought into the effective range of the guidesurfaces which slope in relation to the longitudinal axis of thehousing, from which they slide either into the short slots or into thelong slots, depending upon whether the pushbutton has been actuated withthe cartridge in the retracted position or in the forwardly pushedposition. The projections 38 of the driving member 38 are longitudinallydisplaceable in the said slots.

In FIG. 10 the guide surfaces and stops are formed on a heart-shaped cam39 on the outside of the component 34. In this case, the locking memberconsists of a ball 6" which engages in one case in the heart-shaped cam39 and in the other case in a circular slot 41 formed in the innersurface of a part 40 which is also axially displaceable in the housingI. Since this mechanism is known per se, its operation need not bedescribed in detail. When the cartridge is pushed forwards, the lockingpawl 25 of the securing clip 5 cooperates with a flange 42 on the part40, which is pressed under the action of the spring 4 against thelocking pawl 25, as is apparent from FIG. 10. When the locking pawl iswithdrawn from the flange 42, the parts 34 and 40 are shifted to therear until the flange 42 on the part 40 encounters the inwardlyturned-over edge 43 of a sleeve 44 screwed into the housing 1.

The embodiment illustrated in FIG. 11 differs from that according toFIG. 10 substantially in that the locking member 25' engaging theheart-shaped cam 39 is formed on the securing clip 5. The stop whichacts independently of the stops for the locking member 6 which areformed on the heart-shaped cam 39 is formed by the inwardly projectingshoulder 45 of the housing 1, against which shoulder the part 34 formedwith the cam bears in the course of its displacement when the lockingmember 6 is lifted out of the heart-shaped cam 39. In the embodimentsillustrated in FIGS. 10 and 11, the part 34 is integrally connected tothe pushbutton 3".

Instead of the heart-shaped cam in the embodiment according to FIG. 11,there may be provided on the outside of the component 34 guide surfacesand stops for the locking member 6, which are formed as shown in FIG.12. Such a construction is known in principle, so that it need not befurther discussed, In the constructions of FIGS. 9 to 12, the lockingmember is normally held in engagement with the guide surfaces and stopsby means of the clip pressed against the housing under the action of aresilient return force. This engagement is broken only when a materialis introduced between the clip and the housing.

The embodiment illustrated in FIGS. 13 and 14 is distinguished fromthose illustrated in FIGS. 9 to 12 by the fact that the locking memberis formed on a tongue which is formed by an incision 46 in the housingwall and which is radially movable in relation tothe longitudinal axisof the housing against the action of a resilient return force, and towhich the clip is so connected that, when it is lifted, the lockingmember 25' becomes disengaged from the stop which arrests the cartridgein its forwardly pushed position, and which in this case is again formedon the heart-shaped cam 39 on the outside of the axially displaceablecomponent 34.

FIGS. 11: to 3b also illustrate the safety measures with which theinvention is additionally concerned, for preventing the housing wallwhich lies in the region of the forward housing aperture 48 from beingsoiled with writing medium. For this purpose, it is proposed inaccordance with the invention, in a writing instrument comprising awriting member constructed as a bundle of fibers 49 and enclosed in anarrow tube 50, to provide in the forward end of the housing, at adistance from the housing aperture 43, a guide for the enclosure tube,which holds the latter at the housing aperture, when the cartridge is inthe forwardly pushed position, at such a distance from the housing wallthat no writing liquid can be drawn into the gap a between the tube 50and the housing 1 by capillary action. In the illustrated embodiment,the guide is formed by extensions SI projecting from the inside of thehousing slightly behind the aperture 48.

It is furthermore proposed to provide behind the guide 51, in spacedrelationship thereto, a cup-shaped cap 52 (see FIG. lb) which masks thewriting member 49 from the housing aperture in the retracted positionand which is adapted to be expanded against the action of the resilientreturn force when the writing member is pressed against the base of thecup, and which is adapted to close automatically under the action of thereturn force when the writing member is retracted from the expandedopening. The angle which the wall portions of the cap 52 which directlybound the expansible opening of the base of the cup enclose with thelongitudinal axis of the housing should be of such size that, even afterthe expansion of the cap, they are at such a distance b" from thehousing wall that the writing liquid which wets the edges of theexpansible aperture cannot be drawn by capillary action into the spacebetween the wall portions of the cup and the housing wall extendingbetween the latter and the forward housing aperture. The base of the cupwhich forms the cap 52 has, as is apparent from FIGS. 1a to 3b, the formof a cone whose aperture or open angle is greater than 90?. in theembodiment illustrated in FIGS. la and 2, the cap 52 may be formed of acup-shaped part consisting of rubber, the edge of the aperture of whichis outwardly turned over and gripped between the spring 4 and a housingshoulder. The expansible aperture is in this case formed by one or moreincisions in the base of the cap.

If the cap consists of an injection-molded plastic part havingrelatively low elasticity, as in the embodiment according to FIG. 3a,and equal slots 53 (see FIG. 3b) are formed in the production of the cap52' it is found necessary to take particular steps to cause those edgesof the flaps of the cap which bound the slots to bear one against theother when the cartridge is in the retracted position. This can be doneby means of a sleeve 54 consisting of highly elastic material, forexample rubber, which is stretched over the cap so that it is expanded,the sleeve being formed with an aperture 55 in its base. Owing to thereturn force produced in the sleeve 54 by the expansion, the flaps ofthe cap 52 are applied one against the other as soon as the cartridge isretracted into its rear position.

In order to avoid damage to the writing member constructed as a bundleof fibers, it is found desirable to round off the inside edge 53' of theexpansible cap.

I claim:

1. A writing instrument comprising, in combination:

a. a hollow housing elongated along an axis of the elongation and havinga forward and a rear end, each end defrm ing an opening;

b. an elongated writing member having two opposite ends and a writingpoint at one of the ends, and arranged within said housing along theaxis of elongation thereof, with said writing point adjacent the forwardend of said housing;

c. a spring means arranged within said housing for biasing said writingmember toward the rear end of said housing;

. an operating means arranged in contact with said writing member at theother of the ends of said writing member for displacing said writingmember along the axis of said housing between a retracted positionhaving said writing point entirely within said housing and an advanceposition wherein said writing point extends out of said housing againstthe bias of said spring means by applying a force parallel to the axisof said housing to said operating member in the direction of the forwardend of said housmg;

e. a securing clip having a free end and arranged outside of andadjacent to said housing near the rear end thereof;

f. means including a locking element formed on said securing clipadjacent the forward end thereof for retaining said writing member inthe advanced position and operable to release said writing member andpermit it to move to its retracted position both when a force parallelto the axis of said housing is applied to said operating member in thedirection of the forward end of said housing and, separately, when thefree end of said securing clip is biased away from said housing in adirection that is substantially perpendicular to the axis of saidhousing; and

g. means separate from said retaining means and coacting with saidoperating means for retaining said writing member in the retractedposition after said securing clip is biased away from said housing.

2. The writing instrument as defined in claim 1, further including aconnecting portion connecting said operating means to said securing clipadjacent the rear end of said securing clip, an axially extending slotin said housing receiving said connecting member and effective toprevent rotation of the operating means, and guide surfaces and stopsfor said locking element formed on the outside of the housing andcooperating with said locking element to form said advanced positionretaining means.

3. A writing instrument as definedin claim 2, further including aresiliently outwardly urged pawl formed on said operating means, and arecess in said housing, said pawl engaging said recess in the retractedposition of the writing member to form said separate retaining means.

4. A writing instrument as defined in claim 3, wherein a portion of saidsecuring clip extends forwardly of said locking element and slopesoutwardly from the housing to facilitate the introduction of thematerial of a pocket between said securing clip and said housing.

5. A writing instrument as defined in claim 2, wherein there is formedon the exterior of said housing:

a. a rearmost, a central, and a foremost inclined guide surface, axiallyspaced from one another, against which said locking element bears, andall inclined in the same sense with respect to the axis of elongation ofsaid housing;

b. a stop surface at the rear end of said central guide surface which iseffective to engage said locking element when the writing member is inits advanced position;

c. a transfer guide surface between each of said three axially spacedguide surfaces; and

. a further stop surface arranged to be effective on movement of thelocking element from said rearmost guide surface to said central guidesurface to prevent said locking element from being deflected as far asthe respective one of said transfer guide surfaces connecting saidforemost guide surface to said rearmost guide surface, so as to skip thestop surface formed on the end of the central guide surface.

6. A writing instrument as defined in claim 2 wherein there is formed onthe outside of said housing;

a. a rearmost, a central and a foremost inclined guide surface, whichare axially spaced from one another and against which said lockingelement bears, the inclination of the rearmost guide surface to the axisof elongation of said housing being opposite to that of the central andforemost guide surface;

. a stop surface at the rear end of said central guide surface arrangedto be effective to engage said locking element when said writing memberis in its advanced position;

c. a transfer guide surface between each of said three axially spacedguide surfaces; and

d. a further stop surface arranged to be effective on movement of saidlocking element from said central guide surface to said foremost guidesurface to prevent said locking element from being deflected in thedirection of said transfer surface from said rearrnost guide surface tosaid central guide surface.

7. A writing instrument as defined in claim 1, further comprising amember which is displaceable rearwardly under the action of said springmeans, said member having stops and guide surfaces formed thereon, andthe locking element associated with said securing clip being a lockingpawl, said locking pawl engaging said member to prevent movement thereofto the retracted position.

8. A writing instrument as defined in claim 7, wherein said locking pawlcomprises an extension of said securing clip, and wherein said housinghas a wall and defines an aperture in said wall, through which saidextension passes to engage said member.

9. A writing instrument as defined in claim 7, wherein said locking pawlhas a tongue in the form of an incision in said housing, said tonguebeing raised from said member when said securing clip is biased awayfrom said housing.

10. A writing instrument as defined in claim'7, further including anannular extension on that portion of said operating means which extendsinto said housing to form a limiting stop for said member when saidmember is shifted rearwardly.

11. A writing instrument as defined in claim 1 wherein said securingclip is connected to said operating means and said operating means isadapted to swivel about an axis perpendicular to the axis of saidhousing when said securing clip is lifted, and further comprising twooutwardly urged, radially resilient pawls on said operating means, andstops and guide surfaces on the interior of said housing, said stops andguide surfaces cooperating with one of said pawls to form said retainingmeans for the advanced position, and a recess in said housingcooperating with said two pawls upon the biasing away of said securingclip, said one of said pawls being so arranged that on the biasing ofsaid securing clip it disengages from one of said stops which arrestsaid writing member in its advanced position.

12. A writing instrument as defined in claim 1 wherein said writingmember comprises a bundle of fibers enclosed in a tube having an outerdiameter, and said housing has an inner diameter substantially largerthan said outer diameter and defined by a wall and is provided with aguide means for said tube at the forward end of said housing, whichguide means is axially spaced from the opening defined in the forwardend and is effective for guiding said tube in said opening when saidwriting member is in its advanced position, and is located at such adistance from said housing wall for assuring that no writing ink cancontact said housing under the influence of capillary action in the gapbetween said tube and said housing.

1. A writing instrument comprising, in combination: a. a hollow housingelongated along an axis of the elongation and having a forward and arear end, each end defining an opening; b. an elongated writing memberhaving two opposite ends and a writing point at one of the ends, andarranged within said housing along the axis of elongation thereof, withsaid writing point adjacent the forward end of said housing; c. a springmeans arranged within said housing for biasing said writing membertoward the rear end of said housing; d. an operating means arranged incontact with said writing member at the other of the ends of saidwriting member for displacing said writing member along the axis of saidhousing between a retracted position having said writing point entirelywithin said housing and an advance position wherein said writing pointextends out of said housing against the bias of said spring means byapplying a force parallel to the axis of said housing to said operatingmember in the direction of the forward end of said housing; e. asecuring clip having a free end and arranged outside of and adjacent tosaid housing near the rear end thereof; f. means including a lockingelement formed on said securing clip adjacent the forward end thereoffor retaining said writing member in the advanced position and operableto release said writing member and permit it to move to its retractedposition both when a force parallel to the axis of said housing isapplied to saId operating member in the direction of the forward end ofsaid housing and, separately, when the free end of said securing clip isbiased away from said housing in a direction that is substantiallyperpendicular to the axis of said housing; and g. means separate fromsaid retaining means and coacting with said operating means forretaining said writing member in the retracted position after saidsecuring clip is biased away from said housing.
 2. The writinginstrument as defined in claim 1, further including a connecting portionconnecting said operating means to said securing clip adjacent the rearend of said securing clip, an axially extending slot in said housingreceiving said connecting member and effective to prevent rotation ofthe operating means, and guide surfaces and stops for said lockingelement formed on the outside of the housing and cooperating with saidlocking element to form said advanced position retaining means.
 3. Awriting instrument as defined in claim 2, further including aresiliently outwardly urged pawl formed on said operating means, and arecess in said housing, said pawl engaging said recess in the retractedposition of the writing member to form said separate retaining means. 4.A writing instrument as defined in claim 3, wherein a portion of saidsecuring clip extends forwardly of said locking element and slopesoutwardly from the housing to facilitate the introduction of thematerial of a pocket between said securing clip and said housing.
 5. Awriting instrument as defined in claim 2, wherein there is formed on theexterior of said housing: a. a rearmost, a central, and a foremostinclined guide surface, axially spaced from one another, against whichsaid locking element bears, and all inclined in the same sense withrespect to the axis of elongation of said housing; b. a stop surface atthe rear end of said central guide surface which is effective to engagesaid locking element when the writing member is in its advancedposition; c. a transfer guide surface between each of said three axiallyspaced guide surfaces; and d. a further stop surface arranged to beeffective on movement of the locking element from said rearmost guidesurface to said central guide surface to prevent said locking elementfrom being deflected as far as the respective one of said transfer guidesurfaces connecting said foremost guide surface to said rearmost guidesurface, so as to skip the stop surface formed on the end of the centralguide surface.
 6. A writing instrument as defined in claim 2 whereinthere is formed on the outside of said housing: a. a rearmost, a centraland a foremost inclined guide surface, which are axially spaced from oneanother and against which said locking element bears, the inclination ofthe rearmost guide surface to the axis of elongation of said housingbeing opposite to that of the central and foremost guide surface; b. astop surface at the rear end of said central guide surface arranged tobe effective to engage said locking element when said writing member isin its advanced position; c. a transfer guide surface between each ofsaid three axially spaced guide surfaces; and d. a further stop surfacearranged to be effective on movement of said locking element from saidcentral guide surface to said foremost guide surface to prevent saidlocking element from being deflected in the direction of said transfersurface from said rearmost guide surface to said central guide surface.7. A writing instrument as defined in claim 1, further comprising amember which is displaceable rearwardly under the action of said springmeans, said member having stops and guide surfaces formed thereon, andthe locking element associated with said securing clip being a lockingpawl, said locking pawl engaging said member to prevent movement thereofto the retracted position.
 8. A writing instrument as defined in claim7, wherein said locking pawl comprises an extension of said securingclIp, and wherein said housing has a wall and defines an aperture insaid wall, through which said extension passes to engage said member. 9.A writing instrument as defined in claim 7, wherein said locking pawlhas a tongue in the form of an incision in said housing, said tonguebeing raised from said member when said securing clip is biased awayfrom said housing.
 10. A writing instrument as defined in claim 7,further including an annular extension on that portion of said operatingmeans which extends into said housing to form a limiting stop for saidmember when said member is shifted rearwardly.
 11. A writing instrumentas defined in claim 1 wherein said securing clip is connected to saidoperating means and said operating means is adapted to swivel about anaxis perpendicular to the axis of said housing when said securing clipis lifted, and further comprising two outwardly urged, radiallyresilient pawls on said operating means, and stops and guide surfaces onthe interior of said housing, said stops and guide surfaces cooperatingwith one of said pawls to form said retaining means for the advancedposition, and a recess in said housing cooperating with said two pawlsupon the biasing away of said securing clip, said one of said pawlsbeing so arranged that on the biasing of said securing clip itdisengages from one of said stops which arrest said writing member inits advanced position.
 12. A writing instrument as defined in claim 1wherein said writing member comprises a bundle of fibers enclosed in atube having an outer diameter, and said housing has an inner diametersubstantially larger than said outer diameter and defined by a wall andis provided with a guide means for said tube at the forward end of saidhousing, which guide means is axially spaced from the opening defined inthe forward end and is effective for guiding said tube in said openingwhen said writing member is in its advanced position, and is located atsuch a distance from said housing wall for assuring that no writing inkcan contact said housing under the influence of capillary action in thegap between said tube and said housing.